18161559 has 48 divisors (see below), whose sum is σ = 31292352. Its totient is φ = 10036224.

The previous prime is 18161537. The next prime is 18161573. The reversal of 18161559 is 95516181.

It is not a de Polignac number, because 18161559 - 2⁵ = 18161527 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18161509) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 45549 + ... + 45945.

It is an arithmetic number, because the mean of its divisors is an integer number (651924).

Almost surely, 2^18161559 is an apocalyptic number.

18161559 is a deficient number, since it is larger than the sum of its proper divisors (13130793).

18161559 is a wasteful number, since it uses less digits than its factorization.

18161559 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 456 (or 453 counting only the distinct ones).

The product of its digits is 10800, while the sum is 36.

The square root of 18161559 is about 4261.6380653453. The cubic root of 18161559 is about 262.8558873517.

It can be divided in two parts, 1816 and 1559, that added together give a cube (3375 = 15³).

The spelling of 18161559 in words is "eighteen million, one hundred sixty-one thousand, five hundred fifty-nine".